One of the key goals of many modern advanced manufacturing processes is the fabrication of complex structures on a micron or nanometer scale in a fast, reliable and cost-effective manner (Wang et al., Mechanical Engineering 20:10, 2012; Horn et al., Science Progress 95:82, 2012; and Lewis et al., Journal of the American Ceramic Society 89:3599, 2006). It is well accepted that the ability to form highly ordered micro-nano scale structures and surfaces is a pre-requisite for advancement in many fields including; microfluidics (Koster et al., Applied Physics 46:1, 2013), controlled mammalian cell culture (Anil et al., Bio Techniques 53:315, 2012), responsive smart surfaces (Yoshida et al., ACS Nano 20:1101, 2008), micro-mechanical devices (Liva et al., Sensors and Actuators A: Physical 95:143, 2002) and next generation engineering materials (Wang et al., Mechanical Engineering 20:10, 2012; Horn et al., Science Progress 95:82, 2012; and Lewis et al., Journal of the American Ceramic Society 89:3599, 2006).
While the majority of current methods (e.g. 3D-printing) for high-resolution, high-aspect-ratio patterning rely on the direct formation of a structure, pattern or repeat unit at the desired size-scale. The lower limits of the pattern dimensions are therefore constrained by the current state of the art in the engineering tools employed to physically pattern these structures (Lemu et al., AIP Conference Proceedings 1431:857, 2012; Wang et al., Mechanical Engineering 20:10, 2012; and Horn et al., Science Progress 95:82, 2012).
There have been efforts in the field that are focused on reducing the size scale of soft lithographic (Koster et al., Applied Physics 46:1, 2013), additive manufactured structures (Wang et al., Mechanical Engineering 20:10, 2012), and in actuation (Yoshida et al., ACS Nano 20:1101, 2008) and mechanical modification of materials as a function of external forces (Liva et al., Sensors and Actuators A: Physical 95:143, 2002). Most notably, Grime et al. demonstrated the use of commercially produced biaxially oriented polystyrene to realize the thermal shrinkage of microfluidics patterns (Grime et al., Lab Chip 8:170, 2008). However, their process is neither tunable nor reversible and is limited to polystyrene.
Thus, a need exists for a novel and effective system for controllable and reversible isotropic size-scale reduction or expansion of complex 3D structures using silicone polymer chemistry. The ideal approach should have versatile silicone chemistry, elegant simplicity, relatively low materials cost, broad applicability, tunable material properties, and ease of manufacturing.